Circular cutter



March 2, 1948. l P. E. RIVEST i 2,436,899

CIRCULAR CUTTER Filed Dec. 5, `1945 PAUL fucL/ Riv/55T Patented Mar. 2, 1948 A matassa I y t* fontcUnnoUTn-*ER l raul Euclid inivest, Lancom-ontario, centran 'Appiicati'enneceibera1945,-sefiaiinbstscgsez'" This invention relatesigenerallyxtosheet 'metal cutters 'usedin "cutting circular *holes lorcircular sections of comparatively largediameters.

The `primary "object-'offthis invention'` isf tojprovides-tool for cutting circular sections A"in sheet 1 material lby attaching saiditoo'l "to a Adrill press VYor any otherfsimilarrotating ytoolofstandarddesign;

Another "objectfi-the finventionisto providea'A taehrnentzhavingifour `Yeuuzing units (for space means bywhich ,annular-sections'ican'be cutin sheet material-by 4'cutting several Aconcentric cir:

cles simultaneously, l y t And iyet 'another object jf *the fsaid invention is to provide anleconomic'atiand compact lcircular cutting attachment which'r'nay be'attached tto standard emachineshopfequipment'y thereby felini# inating 4the cost vf gand j'space hoccupied 'by llarge [individual machines ffor J'that' purpose.

The-foregoinglobjects togetherwith othe'rswill be apparent ffrom :the ffllcu'rirg d'esc`:ription M:corr-L sidered in connection withthe atta-'chedfdrawin'g's in'whichh e' f Figure 1 is -a partial "plan of `the inventionf: Figure l2 `is an *elevation 'of A"the `inventiori; 'and' Figure r3 is 'a detailo'fithe centering :dev/ice;fand Figure 4 shows4 a variationinfthe fctting" tool.

Similar :numerals refer' to :similar parts' throughoutfthe*severalfviews- The central sliaft *by means' ``of whi cutter is attached 'tOlai-'dr'ill 1pressthrou Y medium'fofa chuckor`ftaperthe upper-Tand lower plates V"5 and l1, respectively, and -'the -four ysep` arating walls 9constitute the frameworkpfthe cutter. `A4rlheupper'platei'is provided with ribs 6 for reinforcement,purposesand.the..lower plate 1 is provided with'slot's toperiii'ittle travel of the cutterholders l.` y Y The cutting of circular holes tor sections is accomplished r.loyameansr ofiV .circular sharp-edged disks 3, by eompressmgtnsaid'cutters or disks tl against the sheet to be cutfinfthe usual manner after the -said rattachment wh' @been attached to the spindleV of the drill-press; The disks are rotatably supported by a clevisllike fho'lderi .2 which is in turn inserted into the adjustable cutter holders I, and held rigidly therein by set screws or similar fasteners.

The adjustable cutter holders I are arranged symmetrically about the central shaft 4 so that the axis of one pair of said holders is atfright angles to the axis of the other pair of saidholders. In Figure 1 is shown a circular cutting ateconomy, fone'iidentical `cutting unit has 'been omitted:inthe:dra;wing oflthe plan). However,

any isili-table fnumbe'r r ofsuch cutting units .may be incorporatediint'o :the attachment, `suchV units being symmetrically fspaced :about hand radiating fromt'h'efc'entralrshaft 4.

Thefdista'ncef-fbetween .the icuttersandthe center `of, the Aattachment als adjusted fby fmeans iof bolts :l iwhichi'p'assthrough ihle "I3 in the walls 9, through atapped .hole iiin'f'the hlders il, and are ,-locselyiernbedded :for a 1 short :distance :into the "wallof V:the rce'ntral rshaft 14. IIhe fbolt :I0 is provided fwith an annularigrooveiinto which :ts

a f'splitzwas'her f4'. ..The .isaid fwasher is yattaclcle'd to athefwall 59 :andi therebyzprevents the :movement of th'ebolt Il); infand out :of ithe'iw'all 9. The .,b'olt to facilitatev the turning A:of :the fbolt I turning fof `the said boltv ineither direction f causes thefholder :I -withtzits attached cutter v3 'to fnovef tbzand ffrom the 'central shaft 4, 4.thereby adjust The :lowerkguidingfrodil5' lis similarly anchored and iti'pass'es:throughiaihole in fthe 'lower end ,of

thezholder i Y e ilorproviderfurther sst'ability ,togthe holders :I andtm allow more 'accurate adjustment,y a spring I-Biis f wound'iaround'each .of the Liguiding frods it and iteand iskheldzinfcompression between the central-'shaft .4 and :the-innerrface :of ieachof the holders il. Y I :,The `central-zshait=1lcor1stitutesLthe spindle-of the attachment. `altfmayibetubularfand of .uniiorm zdiameter ithrouglxoutfits entire i;length, :cor itmayitaperrtoward's itswiend afar :attachment to asstandardad'rill pressispndlet, {Fheshaft \4 `has a hollow interior I1 which terminates into a hole 2| at the bottom end of the said shaft. The hole 2| is of a smaller diameter than I1.

The hollow shaft 4 contains a centering device comprising a pointed pin I9 which is freek to pass through the hole 2 I, and a weighted part 22 which is the upper part of said pin. The part 3 22 is slightly smaller in diameter than the hollow section Il so that it is free to slide therein but ls too large to pass through the hole 2|.

The framework of the attachment is held together by a series of screws I8 which pass through the upper and lower plates and I respectively, and screw into the walls 9. i Other rigid parts of the said attachment are either spot welded, force fitted, or similarlyv4 attached to the framework in their respective .positionsr The operation ofthe invention consists of attaching the circular cutter to a standard drill press by fastening the shaft 4 to the chuck or` sleeve of the spindle. The material to be cut is placed upon the table of the press andcentered by means of the retractible centering point I9:

The press is set into rotation and the lever hand n feed is pressed down so that the cutting disks 3 press into the material to be cut. The pressure f have to be providedwith a `suitable table to ac commodate the inverted attachment.

i The'centering device as shown in Figure 3 of the drawings,.is vto be used strictly as such. It has no pivoting value, and is made retractible so that the pressure applied to Athe cutting attachment will not vcause it to penetrate the material which is being cut, and the said centering point will not become distorted after several applications of the device. i 5

l For cutting metals of heavy gauge, the cutters 3 with their brackets 2 can. bereplaced by a tool holder 23 into which .is inserted in the usual mannerva standard cutting tool 24, as shown inV Figure 4.

` It is obvious that changes may be made in the device by those skilled in the artwithout departing from the essentials of the invention, I therefore do not-eonsiderthe invention limited t`othe specific construction shown by Way of eX- ample `in the above specification, but what I claim is:

. 1. A circular cutting-attachment forn a drill.

said attachment; a plurality of symmetrically spaced adjustable cutter holders contained within said framework and extending. through the slots 'in the lower plate, a corresponding number of circular rotating cutting disks, one Vattached to each of said holders; Vthreaded adjustablerbolts passing through and rotatably held 'against the walls of the framework, said bolts being rotatably supported at their other ends by the central shaft and being screwed through tapped holes in the said cutter holders, said bolts being further provided with knurled heads and lock nuts; and each of said cutter holders being guided by a pair or guide bars which pass through said cutter holders and are anchored by theframework wall and the central shaft. g

' 2. Acircula;` cutting attachment lsuch as described in claim 1 provided with a spring wound about each of said guide bars, and said spring beingv held in compression between the inner face of said cutter holder and the said central shaft.

3. A'- circular cutting attachment such as described in claim 1, the central shaft being provided with a retractible centering device comprising aweighted pin which hangs by means of gravity from the bottom end of the said central shaft and which slides into the hollow Yinterior of the said shaft when pressure is applied to the point of said centering device.

4. In aidrill-press attachment, a circulary cutting means comprising an upper plate reinforced with ribs radiating fromy its center, a lower corresponding plate provided with a plurality of symmetrically spaced slots,a plurality of sectional walls separating said plates, a central hollow shaft having at the upper end thereof a, taper for attachment to a drill-press spindle, attached to said plates extending upwardly beyond the upper plate and terminating with the lower plate, the above items constituting the framework of said attachment; a plurality of symmetrically spaced adjustable cutter holders contained within said framework Vand extending through the slots in the lower plate, a corresponding number of circularrotating cutting disks, one attached to each of said holders; threaded adjustable bolts passing through and rotatably held against the walls of the framework, said bolts being rotatably supported at their other ends by the central shaft and being screwed through tapped holes in the said cutter holders, said bolts being further provided with knurled heads and lock nuts; and each of said cutter holders being guidedby-a pair of guidebars which pass through said cutter hold- REERENCES CITED The following references are of record in the file of this patent: A

Y UNITED STATES PATENTS Number Name Date 1,537,376 ,Prosser May 12, 1925 1,746,463 lElder Feb. 11, 1930 Witter Feb. 6, 1945 

